This dissertation explores the construction of identity and memory in the Middle Ages within the liturgical cult of Saint Denis, one of the most important yet most contested saints. Gregory of Tours (d. 594) identified this Dionysius as a bishop sent to evangelize Gaul in the third century. According to his ninth-century passio by Abbot Hilduin, however, he was Dionysius the Areopagite, the biblical convert of the Apostle Paul (Acts 17:34), and the mystical theologian of the East who wrote under that name. Moreover, called as the Apostle of all Gaul by the first-century Pope Clement, he became the martyred first bishop of Paris who carried his severed head to his chosen burial place. Some people questioned this conflation, including the scholar-monk Peter Abelard (1079-1142), yet many centers in France sought a connection to Saint Denis, the special patron of the king and kingdom. Over time, a network of subordinate companions evolved, who were said to have evangelized cities throughout Gaul. Using both hagiography and the musical forms of the liturgy, medieval communities rewrote their histories and established identities tied to Saint Denis and all that he represented: apostolic authority, early evangelization, and temporal power.

Beginning at the royal abbey, Part I of the dissertation surveys the annual liturgies that established the identity of Saint Denis (his feast day, Vigil, and Octave), as well as a weekly commemoration instituted by Abbot Suger soon after Abelard's challenge to this identity. Part II turns to the cult of Saint Denis beyond the abbey. It explores liturgical manifestations of the Areopagite controversy, including a separate Areopagite feast at Chartres, and examines the use of Dionysian liturgies in the remembrance of companion saints Caraunus of Chartres and Nigasius of Rouen. Part III returns to the sung histories of the royal abbey. It reviews the liturgies that defined the holy locus of the saint (his Invention, the Consecration of the Altar, and the Dedication of the Church) and relates them to Suger's building campaigns. It also illustrates the musical commemoration of a joint identity for the king-saint Louis and the royal patron Saint Denis.